/**
 * @author aleeper / http://adamleeper.com/
 * @author mrdoob / http://mrdoob.com/
 * @author gero3 / https://github.com/gero3
 * @author Mugen87 / https://github.com/Mugen87
 * @author neverhood311 / https://github.com/neverhood311
 *
 * Description: A THREE loader for STL ASCII files, as created by Solidworks and other CAD programs.
 *
 * Supports both binary and ASCII encoded files, with automatic detection of type.
 *
 * The loader returns a non-indexed buffer geometry.
 *
 * Limitations:
 *  Binary decoding supports "Magics" color format (http://en.wikipedia.org/wiki/STL_(file_format)#Color_in_binary_STL).
 *  There is perhaps some question as to how valid it is to always assume little-endian-ness.
 *  ASCII decoding assumes file is UTF-8.
 *
 * Usage:
 *  var loader = new STLLoader();
 *  loader.load( './models/stl/slotted_disk.stl', function ( geometry ) {
 *    scene.add( new THREE.Mesh( geometry ) );
 *  });
 *
 * For binary STLs geometry might contain colors for vertices. To use it:
 *  // use the same code to load STL as above
 *  if (geometry.hasColors) {
 *    material = new THREE.MeshPhongMaterial({ opacity: geometry.alpha, vertexColors: THREE.VertexColors });
 *  } else { .... }
 *  var mesh = new THREE.Mesh( geometry, material );
 *
 * For ASCII STLs containing multiple solids, each solid is assigned to a different group.
 * Groups can be used to assign a different color by defining an array of materials with the same length of
 * geometry.groups and passing it to the Mesh constructor:
 *
 * var mesh = new THREE.Mesh( geometry, material );
 *
 * For example:
 *
 *  var materials = [];
 *  var nGeometryGroups = geometry.groups.length;
 *
 *  var colorMap = ...; // Some logic to index colors.
 *
 *  for (var i = 0; i < nGeometryGroups; i++) {
 *
 *		var material = new THREE.MeshPhongMaterial({
 *			color: colorMap[i],
 *			wireframe: false
 *		});
 *
 *  }
 *
 *  materials.push(material);
 *  var mesh = new THREE.Mesh(geometry, materials);
 */

export default function (THREE) {
    let {
        BufferAttribute,
        BufferGeometry,
        FileLoader,
        Float32BufferAttribute,
        Loader,
        LoaderUtils,
        Vector3
    } = THREE;
    
    
    var STLLoader = function ( manager ) {
    
        Loader.call( this, manager );
    
    };
    
    STLLoader.prototype = Object.assign( Object.create( Loader.prototype ), {
    
        constructor: STLLoader,
    
        load: function ( url, onLoad, onProgress, onError ) {
    
            var scope = this;
    
            var loader = new FileLoader( scope.manager );
            loader.setPath( scope.path );
            loader.setResponseType( 'arraybuffer' );
            loader.load( url, function ( text ) {
    
                try {
    
                    onLoad( scope.parse( text ) );
    
                } catch ( exception ) {
    
                    if ( onError ) {
    
                        onError( exception );
    
                    }
    
                }
    
            }, onProgress, onError );
    
        },
    
        parse: function ( data ) {
    
            function isBinary( data ) {
    
                var expect, face_size, n_faces, reader;
                reader = new DataView( data );
                face_size = ( 32 / 8 * 3 ) + ( ( 32 / 8 * 3 ) * 3 ) + ( 16 / 8 );
                n_faces = reader.getUint32( 80, true );
                expect = 80 + ( 32 / 8 ) + ( n_faces * face_size );
    
                if ( expect === reader.byteLength ) {
    
                    return true;
    
                }
    
                // An ASCII STL data must begin with 'solid ' as the first six bytes.
                // However, ASCII STLs lacking the SPACE after the 'd' are known to be
                // plentiful.  So, check the first 5 bytes for 'solid'.
    
                // Several encodings, such as UTF-8, precede the text with up to 5 bytes:
                // https://en.wikipedia.org/wiki/Byte_order_mark#Byte_order_marks_by_encoding
                // Search for "solid" to start anywhere after those prefixes.
    
                // US-ASCII ordinal values for 's', 'o', 'l', 'i', 'd'
    
                var solid = [ 115, 111, 108, 105, 100 ];
    
                for ( var off = 0; off < 5; off ++ ) {
    
                    // If "solid" text is matched to the current offset, declare it to be an ASCII STL.
    
                    if ( matchDataViewAt( solid, reader, off ) ) return false;
    
                }
    
                // Couldn't find "solid" text at the beginning; it is binary STL.
    
                return true;
    
            }
    
            function matchDataViewAt( query, reader, offset ) {
    
                // Check if each byte in query matches the corresponding byte from the current offset
    
                for ( var i = 0, il = query.length; i < il; i ++ ) {
    
                    if ( query[ i ] !== reader.getUint8( offset + i, false ) ) return false;
    
                }
    
                return true;
    
            }
    
            function parseBinary( data ) {
    
                var reader = new DataView( data );
                var faces = reader.getUint32( 80, true );
    
                var r, g, b, hasColors = false, colors;
                var defaultR, defaultG, defaultB, alpha;
    
                // process STL header
                // check for default color in header ("COLOR=rgba" sequence).
    
                for ( var index = 0; index < 80 - 10; index ++ ) {
    
                    if ( ( reader.getUint32( index, false ) == 0x434F4C4F /*COLO*/ ) &&
                        ( reader.getUint8( index + 4 ) == 0x52 /*'R'*/ ) &&
                        ( reader.getUint8( index + 5 ) == 0x3D /*'='*/ ) ) {
    
                        hasColors = true;
                        colors = new Float32Array( faces * 3 * 3 );
    
                        defaultR = reader.getUint8( index + 6 ) / 255;
                        defaultG = reader.getUint8( index + 7 ) / 255;
                        defaultB = reader.getUint8( index + 8 ) / 255;
                        alpha = reader.getUint8( index + 9 ) / 255;
    
                    }
    
                }
    
                var dataOffset = 84;
                var faceLength = 12 * 4 + 2;
    
                var geometry = new BufferGeometry();
    
                var vertices = new Float32Array( faces * 3 * 3 );
                var normals = new Float32Array( faces * 3 * 3 );
    
                for ( var face = 0; face < faces; face ++ ) {
    
                    var start = dataOffset + face * faceLength;
                    var normalX = reader.getFloat32( start, true );
                    var normalY = reader.getFloat32( start + 4, true );
                    var normalZ = reader.getFloat32( start + 8, true );
    
                    if ( hasColors ) {
    
                        var packedColor = reader.getUint16( start + 48, true );
    
                        if ( ( packedColor & 0x8000 ) === 0 ) {
    
                            // facet has its own unique color
    
                            r = ( packedColor & 0x1F ) / 31;
                            g = ( ( packedColor >> 5 ) & 0x1F ) / 31;
                            b = ( ( packedColor >> 10 ) & 0x1F ) / 31;
    
                        } else {
    
                            r = defaultR;
                            g = defaultG;
                            b = defaultB;
    
                        }
    
                    }
    
                    for ( var i = 1; i <= 3; i ++ ) {
    
                        var vertexstart = start + i * 12;
                        var componentIdx = ( face * 3 * 3 ) + ( ( i - 1 ) * 3 );
    
                        vertices[ componentIdx ] = reader.getFloat32( vertexstart, true );
                        vertices[ componentIdx + 1 ] = reader.getFloat32( vertexstart + 4, true );
                        vertices[ componentIdx + 2 ] = reader.getFloat32( vertexstart + 8, true );
    
                        normals[ componentIdx ] = normalX;
                        normals[ componentIdx + 1 ] = normalY;
                        normals[ componentIdx + 2 ] = normalZ;
    
                        if ( hasColors ) {
    
                            colors[ componentIdx ] = r;
                            colors[ componentIdx + 1 ] = g;
                            colors[ componentIdx + 2 ] = b;
    
                        }
    
                    }
    
                }
    
                geometry.addAttribute( 'position', new BufferAttribute( vertices, 3 ) );
                geometry.addAttribute( 'normal', new BufferAttribute( normals, 3 ) );
    
                if ( hasColors ) {
    
                    geometry.addAttribute( 'color', new BufferAttribute( colors, 3 ) );
                    geometry.hasColors = true;
                    geometry.alpha = alpha;
    
                }
    
                return geometry;
    
            }
    
            function parseASCII( data ) {
    
                var geometry = new BufferGeometry();
                var patternSolid = /solid([\s\S]*?)endsolid/g;
                var patternFace = /facet([\s\S]*?)endfacet/g;
                var faceCounter = 0;
    
                var patternFloat = /[\s]+([+-]?(?:\d*)(?:\.\d*)?(?:[eE][+-]?\d+)?)/.source;
                var patternVertex = new RegExp( 'vertex' + patternFloat + patternFloat + patternFloat, 'g' );
                var patternNormal = new RegExp( 'normal' + patternFloat + patternFloat + patternFloat, 'g' );
    
                var vertices = [];
                var normals = [];
    
                var normal = new Vector3();
    
                var result;
    
                var groupVertexes = [];
                var groupCount = 0;
                var startVertex = 0;
                var endVertex = 0;
    
                while ( ( result = patternSolid.exec( data ) ) !== null ) {
    
                    startVertex = endVertex;
    
                    var solid = result[ 0 ];
    
                    while ( ( result = patternFace.exec( solid ) ) !== null ) {
    
                        var vertexCountPerFace = 0;
                        var normalCountPerFace = 0;
    
                        var text = result[ 0 ];
    
                        while ( ( result = patternNormal.exec( text ) ) !== null ) {
    
                            normal.x = parseFloat( result[ 1 ] );
                            normal.y = parseFloat( result[ 2 ] );
                            normal.z = parseFloat( result[ 3 ] );
                            normalCountPerFace ++;
    
                        }
    
                        while ( ( result = patternVertex.exec( text ) ) !== null ) {
    
                            vertices.push( parseFloat( result[ 1 ] ), parseFloat( result[ 2 ] ), parseFloat( result[ 3 ] ) );
                            normals.push( normal.x, normal.y, normal.z );
                            vertexCountPerFace ++;
                            endVertex ++;
    
                        }
    
                        // every face have to own ONE valid normal
    
                        if ( normalCountPerFace !== 1 ) {
    
                            console.error( 'THREE.STLLoader: Something isn\'t right with the normal of face number ' + faceCounter );
    
                        }
    
                        // each face have to own THREE valid vertices
    
                        if ( vertexCountPerFace !== 3 ) {
    
                            console.error( 'THREE.STLLoader: Something isn\'t right with the vertices of face number ' + faceCounter );
    
                        }
    
                        faceCounter ++;
    
                    }
    
                    groupVertexes.push( { startVertex: startVertex, endVertex: endVertex } );
                    groupCount ++;
    
                }
    
                geometry.addAttribute( 'position', new Float32BufferAttribute( vertices, 3 ) );
                geometry.addAttribute( 'normal', new Float32BufferAttribute( normals, 3 ) );
    
                if ( groupCount > 0 ) {
    
                    for ( var i = 0; i < groupVertexes.length; i ++ ) {
    
                        geometry.addGroup( groupVertexes[ i ].startVertex, groupVertexes[ i ].endVertex, i );
    
                    }
    
                }
    
                return geometry;
    
            }
    
            function ensureString( buffer ) {
    
                if ( typeof buffer !== 'string' ) {
    
                    return LoaderUtils.decodeText( new Uint8Array( buffer ) );
    
                }
    
                return buffer;
    
            }
    
            function ensureBinary( buffer ) {
    
                if ( typeof buffer === 'string' ) {
    
                    var array_buffer = new Uint8Array( buffer.length );
                    for ( var i = 0; i < buffer.length; i ++ ) {
    
                        array_buffer[ i ] = buffer.charCodeAt( i ) & 0xff; // implicitly assumes little-endian
    
                    }
    
                    return array_buffer.buffer || array_buffer;
    
                } else {
    
                    return buffer;
    
                }
    
            }
    
            // start
    
            var binData = ensureBinary( data );
    
            return isBinary( binData ) ? parseBinary( binData ) : parseASCII( ensureString( data ) );
    
        }
    
    } );
    
    return { STLLoader };
}